Abstract: To improve the last two stage performance of a marine low pressure steam turbine, a redesign process was carried out using blade retrofit and flowpath modification. Then CFD method was used to investigate the turbine flowfield before and after redesign. The computational results show that under the mass flow unchanged condition, the steam turbine performance is increased dramatically with this synthesis optimization design method. The steam turbine efficiency has been increased by 2.162% and its power has been improved by 1.7%.Finally, an experiment about the penultimate rotor was executed. The static pressure coefficient distribution along the blade surface and total pressure loss coefficient distribution along the blade height were measured. The relevant results demonstrate that the blade load distribution of the penultimate rotor is optimized due to retrofit. The secondary flow loss and profile loss are also decreased. 

Key words: Turbine design; Blade retrofit; Flowpath modification; Numerical simulation.

摘要： 为了改进船用汽轮机低压缸末两级涡轮的气动性能,对叶栅和子午流道进行了改型设计,并运用计算流体力学方法对原型方案和改型方案的内部流场进行了数值模拟。计算结果表明,在流量不变的情况下,这种综合优化设计方法能使汽轮机性能大幅提高,最终汽轮机效率提高了2.162%,功率增加了1.7%。最后对次末级动叶进行了环形叶栅试验,测量了叶片表面压力和总压损失沿叶高的分布。试验结果表明,改型设计优化了动叶中的载荷分布,从而有效地降低了叶栅二次流损失和叶型损失。 

关键词: 透平设计;叶片改型;子午流道改型;数值研究 